Search Results (1,639)

This study primarily focuses on the development and optimization of a high-efficiency catalyst for biodiesel production. Potassium carbonate-supported solid catalysts were synthesized using soot as the support material via an equal-volume impregnation method. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses confirmed the successful deposition of potassium carbonate onto the soot surface, resulting in uniformly dispersed spherical nanoparticles on the catalyst. The catalytic performance was evaluated through single-factor experiments, assessing the effects of catalyst loading, alcohol-to-oil molar ratio, reaction temperature, and reaction time on the transesterification reaction. The maximum biodiesel yield obtained from the Single-factor experiments was 95.29% under the optimal conditions of 6 wt% catalyst loading (relative to oil), alcohol-to-oil molar ratio of 14:1, reaction temperature of 60 °C, and reaction time of 3 h. Furthermore, response surface methodology (RSM) using a four-factor, three-level Box–Behnken design (BBD) was employed to systematically analyze the interaction effects of these variables on the biodiesel yield. The optimized conditions identified by RSM were 61.1 °C, 3.3 h, alcohol-to-oil molar ratio of 14.2:1, and 6.1 wt% catalyst dosage, yielding 95.37% biodiesel conversion. These findings demonstrate that the soot-supported potassium carbonate catalyst developed in this study exhibits excellent catalytic activity, offering a novel catalyst system for industrial biodiesel production with significant academic and practical potential. Full article

Recently, the resource utilization of agricultural biomass wastes for the preparation of a wide range of high-value-added chemicals and functional materials, especially heterogeneous catalysts, has received extensive attention from researchers. In this work, mesoporous WO₃/ZrO₂-SiO₂ catalysts are prepared by a two-step incipient-wetness impregnation method using agricultural biomass waste rice husk (RH) as both the silicon source and mesoporous template. The effects of different WO₃ and ZrO₂ loadings on the oxidative desulfurization (ODS) performance of samples are investigated, and the suitable WO₃ and ZrO₂ loadings are 11 and 30%, respectively. The relevant characterization results indicate that, compared to 11%WO₃/SiO₂, the introduction of ZrO₂ leads to the formation of stronger W-O-Zr bonds, which makes the tungsten species stabilized in the state of W⁶⁺. The strong preferential interaction between Zr and W facilitates the formation of stable and highly dispersed WO_x clusters on the mesoporous ZrO₂-SiO₂ carrier. Furthermore, it also prevents the formation of WO₃ crystallites, significantly reducing their content and thus inhibiting the loss of the WO₃ component during cycling experiments. Therefore, the 11%WO₃/30%ZrO₂-SiO₂ sample shows excellent catalytic activity and recycling performance (DBT conversion reaches 99.2% after 8 cycles, with a turnover frequency of 12.7 h^–1; 4,6-DMDBT conversion reaches 99.0% after 7 cycles, with a turnover frequency of 6.3 h^–1). The kinetics of the ODS reactions are further investigated. The mechanism of the ODS reaction is explored through experiments involving leaching, quenching, and the capture of the active intermediate. Finally, a possible reaction mechanism for the ODS process for the 11%WO₃/30%ZrO₂-SiO₂ sample is proposed. Full article

In this work, the mechanical performance of unidirectional thermoplastic laminates produced via a proprietary non-reactive thermoplastic pultrusion system known as the continuous forming machine (CFM) was compared to the mechanical performance of similar laminates produced via compression-molding in a heated platen press. Using commercially available pre-impregnated unidirectional thermoplastic tapes as the material feedstock for both production methods, a comparison of mechanical performance was executed for six separate material systems ranging from commodity-grade (e.g., polypropylene) to aerospace-grade (e.g., low-melt polyaryletherketone) polymer systems. Mechanical performance was evaluated and compared through tensile testing, compression testing, and short beam strength testing in a universal testing machine. The continuous fiber-reinforced thermoplastic (CFRTP) laminates were composed solely of unidirectional plies and were tested in the longitudinal material orientation. Through testing, it was found that the laminates produced on the proprietary thermoplastic pultrusion platform exhibited mechanical performance characteristics equivalent with those of the laminates produced using heated compression-molding. Furthermore, comparisons to values found in the literature were performed, demonstrating the viability of the CFM’s novel manufacturing process to pultrude thermoplastic parts for axially loaded applications. Full article

The eco-toxicological impacts caused by organic pollutants in aquatic environments have emerged as a global concern in recent decades, resulting from the potential hazards they present to ecosystem integrity and human health. Decorating active components on mesoporous silica is considered a popular approach by which to obtain synergistic effects in persulfate activation for sustainable water decontamination. However, at present there has been no review focusing solely, specifically and comprehensively on this field. Therefore, this paper places an emphasis on the latest research progress on the synthesis and physicochemical properties of functionalized mesoporous silica materials as well as their catalytic performance. The preparation methods included co-condensation, impregnation, grinding–calcination, hydrothermal synthesis and chemical precipitation, and their synthesis parameters played a major role in the characterization of materials, thereby affecting pollutant elimination. Metal redox cycles, nonmetallic activation and confinement effects contributed to persulfate activation. Targeted pollutants were degraded via radical pathways, non-radical pathways, or a combination of the two. The effects and causes of operational conditions (catalyst and persulfate dosage, initial pollutant concentration, temperature, initial pH, co-existing anions, and natural organic matter) varied across the degradation systems, and they were categorized and summarized in detail. Furthermore, functionalized mesoporous silica presented excellent reusability, stability and applicability in practical application. Finally, current potential directions for further research and sustainable development in this field were also prospected. This critical analysis aims to fuel the evolution of functionalized mesoporous silica catalyst-driven persulfate system application in water treatment and to bridge prevailing knowledge gaps. Full article

This article presents the manufacturing technology and mechanical properties of innovative pre-impregnated coatings (PCs). The base materials for PC are powders of metal oxides, non-metals, minerals and thermoplastic non-wovens. PC can be used in the manufacture of composites by methods such as vacuum infusion, autoclave curing or hand lamination. This is possible due to the novel PC structure consisting of a functional layer (FL) and a backing layer (BL). PCs are flexible so that they can be used on curved surfaces. In this work, five types of PC were subjected to a uniaxial tensile test. Depending on the powder used, failure force values ranging from 24.61 N to 28.73 N were obtained. In the next step, the pre-impregnated coatings were applied as a coating in “sandwich” composites made by vacuum infusion, which were subjected to three-point bending (3-PB) and adhesion tests. 3-PB tests proved that the coating remained integral with the substrate, even under high flexural deformation, while the adhesion achieved was in the range of 0.95 MPa to 1.57 MPa. PC can be used in many engineering products, e.g., for the coating of façade panels, roof tiles, automotive parts or rail vehicles, etc. Full article

Porous La₂MoWO₉ (W-LAMOX) impregnated with a eutectic mixture of lithium, sodium, and potassium carbonate (LNKC) ceramic membranes was synthesized and evaluated for carbon dioxide (CO₂) sensing applications. Structural, microstructural, and electrical characterizations were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), and impedance spectroscopy. The results indicate that sintered thinner membranes, prepared by the tape casting method, exhibit faster and more reproducible responses to CO₂ exposure than sintered thick pressed pellets. These findings highlight the potential of these composite membranes for application in CO₂ sensing technologies. Full article

Oxygenated volatile organic compounds are key precursors of secondary photochemical pollutants. To enhance their removal, NaY–zeolite was modified with nano-sized metals (Fe, Ti, Si, or Ce) using impregnation and sol–gel methods. Dynamic adsorption experiments were conducted to evaluate the adsorption of ethanol, acetaldehyde, and ethyl acetate under various condition modifications, including of the impregnation concentration, treatment time, and calcination temperature. The structural and surface properties of the modified zeolites were characterized by N₂ adsorption–desorption isotherm, X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FT-IR) analyses. The results indicated that the metal-loaded zeolites exhibited significantly higher adsorption capacities than the unmodified NaY–zeolite. Among them, silicon-modified zeolite showed the best performance, with its adsorption capacities for ethanol, acetaldehyde, and ethyl acetate increasing from 32.4, 72.4, and 123.0 mg·g⁻¹ to 49.82, 88.94, and 207.02 mg·g⁻¹, corresponding to improvements of 37%, 23%, and 70%. The optimal modification conditions involved the use of silicon as the modifier with a 7% impregnation concentration, a 12 h impregnation time, and calcination at 350 °C; the zeolite modified under these conditions was characterized by a good adsorption capacity and low preparation cost. This study suggests newly designed adsorber materials suitable for highly efficient treatment of oxygenated volatile organic compounds. Full article

As the importance of sustainability and performance increases, new developments in the manufacturing of fiber-reinforced polymer composites (FRPC) are requested. Ultraviolet (UV) curing offers a faster, more economical, and eco-friendlier alternative to conventionally used thermal curing methods, e.g., autoclave curing, but according to extant research, also presents some shortcomings, such as limitations to thin FRPCs and transparent glass fibers (GFs). This study analyses the UV light transmission in different thermoset FRPCs by irradiating various fiber samples on one side, while a sensor on the opposite side measures the transmitted irradiance. The materials investigated include unidirectional (UD) carbon fibers (CF), UD flax fibers (FF), and six GF fabrics with different ply structures. The fiber samples are tested in a dry, non-impregnated state and a resin-impregnated state using a UV-curable vinyl-ester-based resin. The results show that up to 16 plies of five GF fabrics are fully cured within the 20 s irradiation time and still exhibit a relatively high light transmission, revealing the potential of curing thick FRPCs with UV light. Furthermore, up to three plies of non-transparent FFs are cured, which is promising for the UV curing of natural fibers. Full article

With the increasing emphasis on environmental protection and sustainable development, improving air pollution control technology has become imperative. In this study, Ce-based catalysts are used as research objects to explore the effects of hydrothermal aging on their performance in oxidizing PM. Different Mn, Na, Pt and Zr-doped Ce-based catalysts were prepared based on the impregnation method and the PM oxidation performance of Ce-based catalysts before and after hydrothermal aging was investigated using thermogravimetric experiments, and the catalytic activity change pattern of fresh/hydrothermal aging Ce-based catalysts was analyzed by comparing the comprehensive combustion index S and combustion stability index Rw, revealing the PM oxidation process. The conclusion showed that the cerium-based catalyst significantly enhanced the oxidation efficiency of PM compared with PU. By comparing the performance of different metal-modified catalysts, it was found that the order of activity was: Pt > Na > Mn > Zr. With the metal doping increased, only the comprehensive combustion index S and combustion stability index Rw of Na/CeO₂ catalysts decreased. After hydrothermal aging treatment, the Zr/CeO₂ catalysts showed the best hydrothermal aging resistance, and the comprehensive combustion index S and combustion stability index Rw remained stable (<5%). Ce-based catalysts have the strongest to weakest hydrothermal aging resistance in the following order: Zr > Mn > Pt > Na. This study not only provides an important scientific reference for the application of Ce-based catalysts in the field of environmental purification but also contributes new ideas and methods to promote the green and sustainable development of air pollution control technology. Full article

Wood is a renewable, carbon-sequestering, and structurally versatile material that has supported human civilization for millennia and continues to play a central role in advancing sustainable development. Although its low density, high specific strength, and esthetic appeal make it highly attractive, its intrinsic flammability presents significant challenges for safety-critical uses. This review offers a comprehensive analysis that uniquely integrates three key domains, covering advanced processing technologies, flame-retardant functionalization strategies, and multifunctional applications. Clear connections are drawn between processing approaches such as delignification, densification, and nanocellulose extraction and their substantial influence on improving flame-retardant performance. The review systematically explores how these engineered wood substrates enable more effective fire-resistant systems, including eco-friendly impregnation methods, surface engineering techniques, and bio-based hybrid systems. It further illustrates how combining processing and functionalization strategies allows for multifunctional applications in architecture, transportation, electronics, and energy devices where safety, durability, and sustainability are essential. Future research directions are identified with a focus on creating scalable, cost-effective, and environmentally compatible wood-based materials, positioning engineered wood as a next-generation high-performance material that successfully balances structural functionality, fire safety, and multifunctionality. Full article

Background/Objectives: Plant-derived bioactive compounds like syringic acid, a phenolic acid from the shikimic acid pathway, have shown potential against chronic diseases, including diabetes, cardiovascular disorders, cancer, and cerebral ischemia. However, its poor water solubility and rapid systemic elimination result in low oral bioavailability, limiting therapeutic potential. This study aimed to enhance its oral bioavailability using MIL-100(Fe), a metal–organic framework (MOF) known for high surface area and drug-loading capacity. Methods: MIL-100(Fe) was synthesized using an optimized method and loaded with syringic acid through impregnation at 12, 24, 36, and 48 h. Characterization included PXRD, FTIR, BET, SEM, and DLS. Acute oral toxicity was evaluated following OECD 423 guidelines, and bioavailability was assessed in Sprague Dawley rats. Results: The 1:2 MIL-100(Fe) to syringic acid ratio achieved the highest drug loading at 64.42 ± 0.03% (12 h). PXRD and FTIR confirmed successful loading (notably at 1239.2 cm⁻¹), and TGA indicated thermal stability at ~350 °C. SEM revealed octahedral particles with an average size of 270.67 ± 2.60 nm. BET showed reduced surface area post-loading. In vitro drug release exhibited media-dependent profiles. Toxicity tests indicated no adverse effects at 2000 mg/kg. Oral administration of SYA@MIL-100(Fe) resulted in a 10.997-fold increase in relative bioavailability versus oral syringic acid and a 12.82-fold increase compared to intraperitoneal administration. Conclusions: MIL-100(Fe) is a safe and effective oral carrier for syringic acid, significantly enhancing its bioavailability. This platform shows strong potential for delivering phenolic compounds in pharmaceutical applications. Full article

Cellulose and lignin are biopolymers with significant potential for chemical synthesis and energy production; however, their heterogeneous composition presents challenges for their use as raw material sources. This study employed near-infrared (NIR) spectroscopy coupled with partial least-squares regression (PLSR) to predict cellulose and lignin content in sapwood and heartwood of Eucalyptus urophylla and sapwood of Pinus taeda, all impregnated with black liquor under high pressure. Samples were analyzed across three longitudinal sections (top, middle, base), with no significant compositional variation detected. Near-infrared spectral data (1100–2500 nm) and pre-processed using the standard normal variate (SNV) method, yielded high predictive accuracy: R² values of 0.98–0.99 for cellulose and 0.94–0.96 for lignin, with root mean square error (RMSE) values of 0.2–0.3 and 0.1, respectively. Principal component analysis (PCA) explained 98% of sample variance, revealing clear distinctions between E. urophylla sapwood and heartwood. These findings confirm the efficacy of NIR-PLSR as a nondestructive, reliable alternative to conventional chemical analyses, with implications for improved quality control and decision-making in the wood treatment industry. Full article

Identifying suitable catalyst types and efficient loading methods remains a key research challenge for implementing the in situ catalytic pyrolysis of tar-rich coal. This study investigated a lignite and a gas coal, employing NiCl₂ solution for Ni²⁺ catalyst loading via room-temperature impregnation and hydrothermal treatment on coal particles sized 6–13 mm. The efficiency of Ni²⁺ loading through hydrothermal treatment and the characteristics of pyrolysis product distribution and composition before and after treatment were examined. The results indicated that after NiCl₂ solution impregnation, the Ni²⁺ content in lignite increased from nearly undetectable to over 20 mg/g, whereas in gas coal, it only rose to less than 2 mg/g. Ion exchange is hypothesized to be a primary pathway for Ni²⁺ loading into coal. After hydrothermal treatment at 170 °C, the Ni²⁺ loadings in lignite and gas coal reached 33.6 and 1.45 mg/g, respectively. The loaded Ni²⁺ exhibited distinct catalytic effects on the two coals. For lignite, Ni²⁺ catalyzed the deoxygenation of oxygen-containing compounds and the aromatization of aliphatic hydrocarbons. For gas coal, hydrothermal treatment with NiCl₂ solution at 170 and 220 °C promoted hydrogen transfer reactions, resulting in an increase in tar yield from 10.67% to 11.30% and 11.64%, respectively. Also, the H₂ yield decreased, accompanied by a decrease in aromatic hydrocarbons and an increase in phenolic compounds within the tar. Full article

This work employed peach stones as the precursor material for producing activated carbon (AC-PS). AC-PS was impregnated with H₃PO₄ and carbonized using a pyrolysis reactor under a reducing atmosphere. The surface area, average pore size, and total pore volume of AC-PS were determined using the BET method. Morphological characteristics of AC-PS were observed through scanning electron microscopy (SEM), the surface composition was identified by energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were conducted to determine the crystalline structure of carbon. The thermal stability of AC-PS and its interactions with lead and cadmium were analyzed by thermogravimetric analyses (TGA/DTG) and infrared spectra (FTIR), respectively. The Elovich model described the adsorption kinetics of both lead and cadmium, and the Weber and Morris model indicated intraparticle diffusion as the controlling mechanism of the adsorption process. The equilibrium study showed that the Freundlich model was adequate for both ions, with adsorption capacities increasing with temperature, reaching around 150 mg g⁻¹ for lead and 80 mg g⁻¹ for cadmium at 45 °C. Economic analysis indicated costs of $0.25 g⁻¹ and $0.51 g⁻¹ for the removal of lead and cadmium from the contaminated water, respectively. Full article

Visceral leishmaniasis is a zoonosis commonly caused in Brazil by the parasite Leishmania infantum. This protozoan parasite can infect several species of mammals, with dogs being the main reservoir in urban areas. Several methods are used to prevent the disease, including collars impregnated with 4% deltamethrin to prevent contact between the sandfly and the animal, and vaccines. Vaccines aim to stimulate an immune response that can effectively fight the parasite, with the Th1 immune response being the most desired. There are several research groups around the world dedicated to testing new immunogens against Leishmania spp. and there are currently two commercially available vaccines used to prevent the disease, Neoleish^® and Leti-Fend^®. Leish-Tec^®, a vaccine previously licensed for use in dogs in Brazil, was suspended in May 2023 due to non-compliance in some batches. This also happened with CaniLeish^®, which was discontinued by the European Commission in October 2023. These vaccines have different characteristics that influence their use as a public health measure, and therefore the objective of this review is to describe these immunogens, their characteristics, and their use as a collective prevention measure for canine visceral leishmaniasis. Full article